Roof Support Structure for a Greenhouse

ABSTRACT

A roof support structure for a flexible roof for a greenhouse is disclosed. The roof support structure comprises an adjustable roof retention portion and a fixed roof retention portion. At least the adjustable roof retention portion is movable between an initial position and at least one adjusted position, wherein the distance between the two roof retention portions, when the adjustable roof retention portion is in any of the adjusted positions, is different from the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position.

FIELD OF THE INVENTION

This invention relates to greenhouses, in particular to those constructed by providing a flexible material over a rigid frame, and more particularly to a roof structure thereof.

BACKGROUND OF THE INVENTION

Greenhouses are commonly constructed using a rigid frame, to which material is attached, forming sidewalls and roof portions. The material varies according to the intended use, and is typically translucent. The material may be made out a flexible material such as polyethylene or special netting.

It is recognized in the art that it is particularly advantageous for the material to be taut, especially on the roof of the greenhouse. This is because sunlight impinging on a taut translucent or transparent surface tends to pass through, to the degree that it is allowed by the material of the roof, relatively uniformly. However, when the same surface develops slack, folds form therein, resulting in non-ideal lighting conditions.

Accordingly, greenhouses made in the way described above are typically constructed so that at least the surfaces forming the roofs thereof are taut. This is accomplished by stretching the material over a roof support structure until it is taut before securing it in place. However, over time, due to a variety of largely unavoidable factors, the material deforms slightly, causing an undesirable slack to develop, leading to the non-ideal lighting conditions within the greenhouse.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a frame for a greenhouse comprising a roof support structure made of flexible material to be tautened when needed, without a need to remove the material and reattach it. According to this aspect, there is provided a roof support structure for a flexible roof for a greenhouse. The roof support structure comprises an adjustable roof retention portion and a fixed roof retention portion. At least the adjustable roof retention portion is movable between an initial position and at least one adjusted position. The distance between the two roof retention portions, when the adjustable roof retention portion is in any of the adjusted positions, is different from the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position. The distance between the two roof retention portions when the adjustable roof retention portion is in any of the adjusted positions may be greater than the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position.

The roof retention portions may be substantially straight, and arranged parallel to one another. The adjustable roof retention portion may constitute an eaves of the roof, and the fixed roof retention portion may constitute the peak of the roof. Alternatively, the adjustable and fixed roof retention portions may constitute opposite eaves of the roof. The adjustable roof retention portion may comprise a gutter.

The adjusted position of the adjustable roof retention portion may constitute a vertical translation thereof from its initial position.

The roof may be made of a material selected from the group comprising polyethylene and netting.

According to another aspect of the present invention, there is provided a greenhouse frame comprising at least one roof support structure as described above.

According to a further aspect of the present invention, there is provided a method of constructing a greenhouse. The method comprises the steps of providing a frame of the greenhouse comprising a roof retention structure having an adjustable roof retention portion and a fixed roof retention portion. At least the adjustable roof retention portion is movable between an initial position and at least one adjusted position, wherein the distance between the two roof retention portions, when the adjustable roof retention portion is in any of the adjusted positions, is different from the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position. The method further comprises the step of providing a sheet of flexible material tautly retained between the adjustable and fixed roof retention portions.

The adjustable roof retention portion may be disposed in the initial position, wherein the distance between the two roof retention portions when the adjustable roof retention portion is in any of the adjusted positions is greater than the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position.

The roof retention portions may be substantially straight, and arranged parallel to one another. The adjustable roof retention portion may constitute an eaves of the roof, and the fixed roof retention portion may constitute the peak of the roof. Alternatively, the adjustable and fixed roof retention portions may constitute opposite eaves of the roof. The adjustable roof retention portion may comprise a gutter.

The adjusted position of the adjustable roof retention portion may constitute a vertical translation thereof from its initial position.

The roof may be made of a material selected from the group comprising polyethylene and netting.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, an embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

FIG. 1 a perspective view of a frame used to construct a greenhouse, comprising a roof support structure according to the present invention;

FIG. 2 is a perspective view of the frame illustrated in FIG. 1, with material secured thereto forming a roof;

FIG. 3 is a closeup perspective view of the end of a gutter being part of the roof support structure of the frame illustrated in FIG. 1;

FIG. 4 is a side view of the gutter according to one modification; and

FIGS. 5A and 5B are perspective views of a gutter and a gutter support member received within a vertical support according to two modifications of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 illustrates a frame, generally indicated at 10, used to construct a greenhouse for which a roof support structure of the present invention may be used. The frame 10 comprises four vertical supports 12 with anchors 14, and a roof support structure, generally indicated at 13. The roof support structure 13 comprises horizontal supports 16, rafters 18, one or more purlins 20, gutters 22, forming the eaves of the roof and constituting adjustable roof retention portions and additional horizontal supports of the frame 10, and a tie beam 24, which constitutes a fixed roof support structure and a peak of the roof support structure 13. It will be appreciated that the frame 10 and roof support structure 13 illustrated in FIG. 1 are only possible arrangements thereof, and should not be construed as limiting. One well-versed in the art will appreciate that any desired structure may be used. Once the frame 10 is erected, material is attached thereto to form the walls and the roof of the greenhouse.

FIG. 2 illustrates the placement of a sheet 26 of material to form the roof. As shown, the sheet 26 is stretched over the roof support structure 13 between the two gutters 22. The material may be polyethylene, greenhouse netting, or any other suitable material.

In order to receive and tightly retain the sheet 26, each gutter 22 comprises a main portion 28 and an insert 30 which tightly fits therein, as illustrated in FIG. 3. The edge of the sheet 26 is placed on an upper surface 33 of the main portion 28 such that it conforms thereto, and the insert 30 placed thereabove. Bolts (not shown) are inserted through through-going apertures 32 in the main portion 28 and insert 30. The bolts serve to secure both the insert 30 and the sheet 26 in place.

Alternatively, as illustrated in FIG. 4, a clamp 34 may be provided to retain the sheet. Several clamps 34 may be provided along the length of the insert 30, or, alternatively, the clamp may be substantially the same length as the insert. The clamp 34 comprises a gripping channel 36, defined by two channel legs 36 a, at the lower edge thereof, and two lever handles 38 at an upper edge. In the absence of any external forces, the clamp 34 is in a neutral state as shown. However, when the lever handles 38 are urged toward one another, the channel legs 36 a separate slightly, which opens the gripping channel 36.

In use, an edge of the sheet 26 is placed on an upper edge 40 of the insert 30. The upper edge 40 is provided with a protrusion 42, which is sized so as to be tightly received within the gripping channel 36 of the clamp 34. The gripping channel 36 is opened as described above, and the clamp is placed on the sheet 26 such that the protrusion 42 is received within the gripping channel through the sheet. The clamp 34 is then allowed the return to its neutral state. The sheet 26 is thereby retained in place by a pressure fit between the clamp 34 and the protrusion 42.

As illustrated in FIG. 5A, the gutter 22 is not fixedly attached to the vertical supports 12 of the frame 10. Rather, a gutter support member 44 is provided, which is adapted to be slidingly received within the vertical support 12. The gutter support member 44 is adapted to be arrested at one of several positions. This may be accomplished, for example, by providing apertures 46 therethrough, and further providing an equivalently sized aperture 48 through one wall of the vertical support 12, such that as the gutter support member slides downwardly inside the vertical support, the aperture formed therethrough is successively aligned with each of the apertures formed within the gutter support member. A bolt or pin (not illustrated) may be placed through the aperture 48 of the vertical support and one of the apertures 46 of the gutter support member, thereby arresting the gutter support member in a desired position. Alternatively, as illustrated in FIG. 5B, a spring-loaded pin 50 may be provided on the gutter support member 44, and apertures 52, sized so as to receive therein the pin, are formed through one wall of the vertical support 12, such that as the gutter support member slides downwardly inside the vertical support, the pin is successively aligned with each of the apertures formed within the vertical support.

In use, the frame 10 is erected with the gutter 22 arrested at its highest position. The sheet 26 is tautly secured between the gutters 22, as shown in FIG. 2, so as to form the roof. Alternatively, the tie-beam 24 may be adapted to grasp the material, so that half-roof portions are formed on each side of the roof. As time elapses, the material will most likely develop slack. In order to tauten the material, the gutter 22 is advanced to a lower position, so that the distance between opposite grasped ends of the material 26 is larger.

It will be appreciated that when the sheet 26 is secured between the gutters 22, only one of the gutters may need to be lowered in order to tauten the entire roof. However, both may be lowered, as the situation warrants.

Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutates mutandis. For example, the tie-beam 24 may be of adjustable height, in addition to, or instead of, the gutters 22. In addition, the gutters 22 may be embodied by an ordinary beam, and does necessarily have to be adapted to channel water that runs off from the roof. 

1. A roof support structure for a flexible roof for a greenhouse, the roof support structure comprising an adjustable roof retention portion and a fixed roof retention portion, at least the adjustable roof retention portion being movable between an initial position and at least one adjusted position, wherein the distance between the two roof retention portions, when the adjustable roof retention portion is in any of the adjusted positions, is different from the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position.
 2. A roof support structure according to claim 1, wherein the distance between the two roof retention portions when the adjustable roof retention portion is in any of its adjusted positions is greater than the distance between the two roof retention portions when the adjustable roof retention portion is in its initial position.
 3. A roof support structure according to claim 1, wherein the roof retention portions are substantially straight, and arranged parallel to one another.
 4. A roof support structure according to claim 1, wherein the adjustable roof retention portion constitutes an eaves of the roof, and the fixed roof retention portion constitutes the peak of the roof.
 5. A roof support structure according to claim 1, wherein the adjustable and fixed roof retention portions constitute opposite eaves of the roof.
 6. A roof support structure according to claim 4, wherein the adjustable roof retention portion comprises a gutter.
 7. A roof support structure according to claim 1, wherein the adjusted position of the adjustable roof retention portion constitutes a vertical translation thereof from its initial position.
 8. A roof support structure according to claim 1, wherein the roof is made of a material selected from the group comprising polyethylene and netting.
 9. A greenhouse frame comprising at least one roof support structure according to claim
 1. 10. A method for constructing a greenhouse, comprising the steps of: (a) providing a frame, said frame comprising a roof support structure having an adjustable roof retention portion and a fixed roof retention portion, at least the adjustable roof retention portion being movable between an initial position and at least one adjusted position, wherein the distance between the two roof retention portions when the adjustable roof retention portion is in any of the adjusted positions is different from the distance between the two roof retention portions when the adjustable roof retention portion is in the initial position; and (b) providing a sheet of flexible material tautly retained between the adjustable and fixed roof retention portions.
 11. A method according to claim 10, the adjustable roof retention portion being disposed in its initial position, wherein the distance between the two roof retention portions when the adjustable roof retention portion is in any of its adjusted positions is greater than the distance between the two roof retention portions when the adjustable roof retention portion is in its initial position.
 12. A method according to claim 10, wherein the roof retention portions are substantially straight, and arranged parallel to one another.
 13. A method according to claim 10, wherein the adjustable roof retention portion constitutes an eaves of the roof, and the fixed roof retention portion constitutes the peak of the roof.
 14. A method according to claim 10, wherein the adjustable and fixed roof retention portions constitute opposite eaves of the roof.
 15. A method according to claim 13, wherein the adjustable roof retention portion comprises a gutter.
 16. A method according to claim 10, wherein the adjusted position of the adjustable roof retention portion constitutes a vertical translation thereof from its initial position.
 17. A method according to claim 10, wherein the roof is made of a material selected from the group comprising polyethylene and netting. 